Life Cycle Analysis of the Operation of Two Greywater Decentralized Treatment Systems

ABSTRACT This study evaluated two decentralized greywater treatment systems using life cycle assessment: a UASB reactor and an aerobic granular sludge SBR (AGS‐SBR). Key impacts, observed in human carcinogenic toxicity, terrestrial toxicity and freshwater toxicity categories, were driven in both systems by energy use and effluent discharge. The UASB outperformed the AGS‐SBR in 17 of 18 categories, often by over 50%, due to its simple, non‐aerated design, making it a more sustainable option. The sensitivity analysis showed that adding a zeolite post‐treatment reduced UASB eutrophication by 12% but increased other impacts. Thus, when considering post‐treatment to improve effluent quality, it is crucial to consider environmental impacts. For the AGS‐SBR, photovoltaic integration cut most impacts by over 50%. These findings underscore the importance of prioritizing low‐energy technologies (UASB) in decentralized greywater treatment. When more efficient and energy‐intensive processes like AGS‐SBR are necessary, supplementing them with renewables is essential to minimize environmental footprints.